1. Field of the Invention
This invention relates to material handling apparatus.
More particularly, the present invention relates to apparatus for gripping and holding containers.
In a further and more specific aspect, the instant invention concerns an apparatus for alternately gripping containers of varied perimeter.
2. The Prior Art
Apparatus for gripping and holding containers or similar articles are well known. Exemplary is the container handling mechanism associated with conventional refuse collection vehicles. The mechanism is utilized to grip, lift and tilt a refuse container for transfer of the contents to the storage bay of the collection vehicle.
A typical container handling apparatus, of particular interest in connection with the instant invention, includes a pair of gripping arms carried at the outboard end of a boom which resides intermediate the storage bay and the cab of a commercially available refuse collection vehicle. Remotely operatable from within the operator's compartment, the mechanism grips and maneuvers a refuse container for transfer of the contents to the receiving hopper of the storage bin.
The boom is reciprocating along a linear path between a retracted position and an extended position. The boom is also angularly movable between a lowered position and an elevated position. An angularly positionable tilt mechanism, pivotably affixed to the outboard end of the boom, supports grip actuating means which are movable between extended and retracted positions. The arms, carried by the grip actuating means, are movable in response thereto between a retracted release position and an extended gripping position.
Normally, as during travel of the vehicle, the boom resides in the lowered retracted position. The arms, being in the extreme release position and extending in substantially opposite directions, reside in close proximity to the side of the vehicle. As the vehicle is brought to a stop adjacent a refuse container, the boom is extended and the arms engaged about the container. The container is then lifted and tilted for deposit of the contents into the hopper. Subsequently, the container is returned to the original location and the handling mechanism regressed to the travel configuration.
Refuse containers are readily available in an array of sizes and shapes. Known, for example, are large stationary containers having a capacity of three hundred to four hundred twenty gallons and a diameter ranging from forty-two to forty-eight inches. Also common are smaller mobile containers with diameters in the range of twenty-two to twenty-eight inches and capacities of sixty to one hundred gallons. The foregoing diameters are taken at the gripping perimeter which resides at approximately twenty-eight inches above the supporting surface. While cylindrical containers are exceedingly common, containers of alternate cross-sectional configuration, such as rectangular, are known.
Various materials, ranging from rigid metal to flexible plastic, are utilized in the fabrication of refuse containers. Particularly favored by the art is polyethylene shaped by various conventional molding processes. The resultant structure includes a comparatively flexible sidewall having a relatively smooth exterior surface. A sidewall taper, usually in the range of four to seven degrees, accommodates mold release and stacking.
The engagement between the arms and the container, which must withstand the lifting, tilting and other maneuvering, is dependent upon the constrictive force of the arms about the container and the friction between respective surfaces. The inherent characteristics of a typical container includes a flexible sidewall with an outer surface having a low coefficient of friction Traditionally, the gripping arms are fabricated of a rigid material, usually metal, also having a relatively low coefficient of friction.
The foregoing characteristics which inhibit satisfactory engagement of the arms with the container are further complicated by other factors. Containers are generally available in two categories, stationary and mobile, having widely variant nominal sizes. Each category is subject to substantial additional variation of diameter and taper. Variation in cross-sectional configuration is also known. Further, the perimeter of a container is frequently distorted as a result of the deposited refuse.
In attempts to alleviate the foregoing problems, the prior art has devised several purported solutions. For example, pads of friction enhancing material have been secured to the normal gripping surface of the arms. Also advanced were flexible arms. However, such solutions have not proven to be entirely satisfactory. Accommodation of variance in cross-sectional size and configuration is extremely narrow, thereby limiting the usefulness of any given pair of arms and the overall efficiency of the respective collection vehicle Even so, when a pair of arms are employed within the given range the frictional contact with the container is less than optimal.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.
Accordingly, it is an object of the present invention to provide improvements in gripping apparatus.
Another object of the invention is the provision of an improved apparatus of the type especially adapted for gripping and holding a container.
And another object of this invention is to provide improvements whereby a gripping apparatus can accommodate containers or other articles having diverse cross-sectional measurements.
Still another object of the invention is the provision of means whereby a pair of fixed-size gripping arms can alternately engage containers of varying cross-sectional configuration.
Yet another object of the instant invention is to provide means for enhancing the frictional engagement between a pair of gripping arms and a container or similar article.
Yet still another object of the invention is the provision of means which will detect and self-adjust for the article to be gripped.
A further object of the invention is to provide an improved pair of gripping arms which are capable of substantially continuous contact with a container having a distorted sidewall.
And a further object of the immediate invention is the provision of improvements which are durably constructed and relatively maintenance free.
Still a further object of the invention is to provide improvements which can be readily practiced in combination with conventional, pre-existing material handling devices, such as refuse collection vehicles.
And still a further object of the invention is the provision of improvements, according to the foregoing, which can be retrofit to prior art gripping arms.